id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
19653	`Manager.get_empty_query_set` should call `get_query_set`	Simon Charette	nobody	"Now that `EmptyQuerySet` has been [https://code.djangoproject.com/ticket/19184 removed] calling `none()` on a `QuerySet` subclass returns an instance that subclass:
{{{
>>> class MyQuerySet(models.query.QuerySet): pass
>>> isinstance(MyQuerySet(MyModel).none(), MyQuerySet)
>>> True # On django >= 1.6
}}}

This is quite useful and less error prone.

However, when one subclass `models.Manager` to return a `QuerySet` subclass they '''must''' override both `get_empty_query_set` and `get_query_set` to have consistent behavior.
{{{
class MyManager(models.Manager):
    def get_query_set(self):
        return MyQuerySet(self.model, using=self._db)


class MyModel(models.Model):
    objects = MyManager()


>>> isinstance(MyModel.objects.none(), MyQuerySet) # Manager.none() calls get_empty_query_set under the hood
>>> False
>>> isinstance(MyModel.objects.all().none(), MyQuerySet)
>>> True
}}}

Another alternative (better IMHO) is to completely remove `get_empty_query_set` since it's not documented and only used by `Manager.none` and `EmptyManager.get_query_set`. We could make `Manager.none` proxy `QuerySet.none` and `EmptyManager.get_query_set` returns `QuerySet.get_query_self(self).none()`.

Attaching two patches that both pass all tests on Python 2.7.3 SQlite."	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	fixed			Ready for checkin	1	0	0	0	0	0